Many jurisdictions prohibit smoking in worl<places and public spaces because of the clear threat to hunnan health, and such prohibitions have been found to result in reduced tobacco use initiation and increased cessation. However, because ofthe sovereign status of federally-recognized American Indian tribes, state smoke-free laws are generally not implemented on tribal lands, and enclosed environments on these tribal lands continue to allow smoking. On the Navajo Nation, there have been concerted efforts led by a Navajo-led coalition called Team Navajo', to eliminate secondhand smoke in workplaces and public places. Team Navajo has worked for two years within the Navajo legislative system for passage of a bill that would prohibit secondhand smoke in Navajo Nation. Though to no avail so far, these efforts are being watched closely as a test case with implications for tribal and other communities across the U.S. and globally. We believe that changing policy regarding secondhand smoke on the Navajo Nation and other tribal communities can only come about through the development and effective implementation of coalitions and partners in a strong, broad and strategic network. This community participatory research will begin with a formative year of instrument development and team building between the researchers and Team Navajo members. Three waves of quantitative social network data in years 2-4 will be augmented with ethnographic data, to examine relationships and communication patterns that have the potential to be optimized for increasing policy change. In addition, contextual factors (e.g. local and state-specific policies, gaming industry efforts, etc.) will be analyzed, including data from all 110 Chapter Houses (the Navajo equivalent of counties), in order to track and explain barriers to policy change, and to evaluate progress. The data will be analyzed with guidance from three different advisory groups, including members of Team Navajo, and findings will be shared with members of Team Navajo and other tribal nations throughout the term of the grant, to maximize the impact of the research. RELEVANCE (See instructions): Tobacco control coalitions often lead efforts towards the passage of smoke-free policies. Our findings will inform how these coalitions can be more effective at building capacity within their communities to result in policy change. What we learn with NATO GAP will be relevant to other indigenous peoples' jurisdictions in the US and beyond, and may be useful to coalition efforts to address other public health issues.